HOMINIDM. 771 



better heel than monkeys have. The arms are shorter than 

 the legs. There is no os centrale. There are 1 2 ribs and 

 1 7 dorso-lumbar vertebrae. 



Compared with the anthropoid apes, man has a bigger 

 forehead, a less protrusive face, smaller cheek-bones and 

 supra-orbital ridges, no sagittal or occipital crests, pro- 

 jecting nasals, an early disappearance of the suture 

 between premaxilla and maxilla, a true chin (hinted at in 

 the Gibbon), more uniform teeth forming an uninterrupted 

 horseshoe-shaped series without conspicuous canines. The 

 body is very naked ; the legs are relatively longer ; the 

 hallux is practically non-opposable ; there are no vocal 

 sacs ; there is at most a vestige of an os penis. 



More important, however, is the fact that the weight of 

 the gorilla's brain bears to that of the smallest brain of 

 an adult man the ratio of 2 : 3, and to the largest human 

 brain the ratio of i : 3 ; in other words, a man may have 

 a brain three times as heavy as that of a gorilla. The brain 

 of a healthy human adult never weighs less than 31 or 32 

 oz. ; the average human brain weighs 48 or 49 oz. ; 

 the heaviest gorilla brain does not exceed 20 oz. '"'The 

 cranial capacity is never less than 55 cubic in. in any 

 normal human subject, while in the Orang and Chimpanzee 

 it is but 26 and 27^ cubic in. respectively." 



But, as Owen allowed long since, there is an "all-pervad- 

 ing similitude of structure " between man and the anthro- 

 poid apes. As far as structure is concerned, there is much 

 less difference between man and the gorilla than there is 

 between the gorilla and the marmoset. 



As regards the much-discussed question of a tail in man, it may be 

 noted that if we define a tail as that part of the body which contains 

 postsacral vertebra and sundry other parts of primitive caudal segments, 

 and -which ?s, moreover^ completely surrounded by integument, then such 

 tails occur always in early embryos of man, and as abnormalities after 

 birth. The abnormalities may be either altogether soft or they may 

 contain bone, but in no case adequately known is there any increase in 

 the number of vertebra.' which normally fuse to form the terminal 

 portion of the human vertebral column, known as the coccyx. 



The arguments by which Darwin and others have sought 

 to show that man arose from an ancestral type common to 

 him and to the higher apes, are the same as those used to 



